Post Activation Potentiation (PAP) - PART II -

Mode of Exercise and PAP

Much of the research on post-activation potentiation such as that performed by Seitz et al. [1] Mitchel et al. [2] Esformes et al. [3] Jo et al. [4] as well as many others has been focused on the use of heavy barbell back squats as an effective means for inducing lower body potentiation. In fact relatively little emphasis has been placed on upper body PAP or other modes of potentiation. However, a small body of research exists demonstrating the use of less traditional training protocols for inducing postactivation potentiation some of which appear to be equally if not more effective than typical approaches previously mentioned. Some of these non-traditional approaches that have been investigated include upper body PAP using traditional free weights, lower body isometrics utilizing maximal voluntary contractions (MVC’s), upper body isometrics utilizing MVC’s, partial range of motion repetitions, vibration training, isokinetic exercise, eccentric-only movements, and concentric-only movements.

Other non-traditional forms of post activation potentiation using loaded movement simulation have also been examined. One study found that shot putters elicited PAP and had greater throwing distance when warming-up with supramaximal shots puts (heavier than normal shot puts), compared to warmed-up conditions that incorporated standard (competition weight shot) or lighter shot put implements [5]. However similar findings have been difficult to reproduce as other loaded movement simulations such as weighted sled sprints have failed to elicit any post activation potentiation response [6]. Some investigators believe that this may be due to disruption of movement mechanics rather than lack of post activation potentiation.

Upper Body Post Activation Potentiation

Relatively few studies have examined the effects of PAP on upper body performance. However most of these demonstrate that upper body results mirror those of lower body post activation potentiation. An investigation by Ferreira et al. [7] indicated that traditional heavy 1 RM bench press when performed roughly seven minutes prior to an explosive movement increased upper body concentric power output. Similarly West et al. [8] found the bench press to be an effective tool for inducing a PAP response when performed with heavy or light loads prior to an explosive upper body exercise.

Isometric Training

Although a majority of studies implement isotonic exercise via the use of traditional free weight movements, several studies have explored the use of isometric exercise for producing a postactivation potentiation effect in both upper and lower body. A study performed by Feros et al. [9] demonstrated the effectiveness of implementing maximal isometric contractions on a rowing machine for improving rowing time in elite level rowers. Another related study performed by Esformes et al. [10] may give greater insight into the use of isometric contractions for producing a short-term potentiating effect. Several types of upper body training techniques were examined in this investigation including traditional dynamic bench press (eccentric and concentric combined) repetitions, eccentric-only bench press, concentric-only bench press, and isometric bench press. The results of this study were surprising as all forms of training failed to induce any significant improvement in the ballistic bench press throw except for the isometric training condition in which there was a significant improvement in peak power. The researchers concluded that isometric bench press was best for causing a post-activation potentiation effect in the upper body although there was no conclusive explanation for this.

It should be noted that longer than normal resting conditions of 12 minutes (time begins from completion of the last training repetition to assessment of dependent variables) were used in this investigation. This could explain why other forms of the bench press movement which have typically shown to be effective in prior research, did not produce post tetanic potentiation. However, Bogdanis et al. [11] reproduced nearly identical findings as Esformes (2011) and his colleagues. In essence there was with no postactivation potentiation effects witnessed in eccentric or concentric training conditions but there was significant PAP found in the isometric condition.

Although the previous findings appear somewhat confounding, other research has drawn similar conclusions demonstrating the superiority of isometric training protocols to more traditional forms of training. A unique study conducted by Rixon et al. [12] compared the effects of performing a traditional back squat to a maximal isometric (MVC) back squat prior to a vertical jump assessment. Although both forms of the back squat were effective for creating a post tetanic facilitation response, the isometric group had significantly greater improvements in vertical jump height and vertical jump power output. Other related literature including research by Pearson et al. [13] Requena et al. [14] and French et al. [15] showed similar results demonstrating the effectiveness of utilizing isometric contractions (MVC’s on knee extension device) for producing post activation potentiation although these studies did not compare isometrics to dynamic free weight exercises or closed chain isometrics (isometric squat).

Range of Motion

Few studies have examined the relationship between range of motion (ROM) and post activation potentiation. However one study performed by Esformes et al. [3] demonstrates critical findings regarding this topic. This investigation compared the potentiation of partial back squats (quarter squats) to parallel squats. Although both conditions induced a PAP response, the parallel squat condition produced the greatest improvements in jump performance. The researchers suggested that because full squats activate the gluteus maximus more effectively than partial squats, this may have been responsible for the difference in the potentiation response witnessed among the two conditions.

Whole Body Vibration Training

Several studies have explored the effect of whole body vibration (WBV) training on post activation potentiation. Because WBV training has been hypothesized to increase intrafusal muscle fiber activation [16], attempts have been made to demonstrate its potentiation effect on performance. However current research in regards to its effectiveness appears to be mixed. For example a study performed by Jordan et al. [17] indicates that WBV in conjunction with a static squat produced no significant post tetanic potentiation effect on torque or force production. However, two similar investigations found whole body vibration training effective for eliciting a PAP response [18, 19] although neither study directly compared these effects to other interventions such as heavy resistance training.

Finally a study performed by Niclario et al. [20] found that whole body vibration created no additional post activation potentiation effects on performance beyond that already witnessed from heavy barbell back squats. Therefore further research is needed to determine the effectiveness of vibration training on PAP particularly when compared to standard resistance training protocols of which many researchers continue to point to as the gold standard for postactivation potentiation programming.

Isokinetic Exercise

Most research investigating PAP has utilized more traditional forms of resistance training including free weights, isometrics, and variable resistance machines. However a unique study conducted by Bautista et al. [21] successfully demonstrated that post-activation potentiation can be produced by performing a series of isokinetic knee extension similar to that witnessed in other studies incorporating traditional free weights. Unfortunately isokinetic exercise may not be as practical as other more traditional forms of training due to equipment size, cost, and convenience.

Training intensity and Loading Parameters

Research surrounding post activation potentiation demonstrates a large range of training intensities and loading parameters that have successfully been used to elicit short-term improvements in performance. However most meta-analysis and reviews have concluded that moderate to heavier loads of 60-84% of 1RM may be most effective for producing PAP [22, 23]. Other studies such those conducted by Lowery et al. [24] demonstrated the effectiveness of slightly higher intensities (70-93% 1RM). Interestingly this same investigation also found lower intensities (55% 1RM) to be ineffective for producing potentiation compared to moderate or higher training loads. Similarly, Weber et al. (2008) found low intensity plyometric jumps inferior to heavy back squats (87% 1RM) for producing post activation potentiation in jump performance.

In contrast, Tobin et al. [26] and Turner et al. [27] found traditional plyometric exercises effective for producing post-activation potentiation. Results appeared to be somewhat similar to PAP produced from heavy resistance exercises (when compared to other investigations) although this was not directly examined (no inclusion of heavy resistance protocol) in either study. It is also suggested that potentiating effects may dissipate more quickly after plyometric movements than typically witnessed with heavy resistance exercise.

Although further research is needed, it appears training load should to be relatively heavy and intense (60-93% 1RM) to achieve a maximal post activation response although other intensities (30-55% or bodyweight plyometrics) may be warranted depending on other training factors and conditions.